The work is directed at correlating the enzymatic activity of the neutrophils with the function (i.e. bactericidal activity) of the cell. Much of the work is concerned with the sequence of events leading to the increase in hexose monophosphate shunt activity which accompanies phagocytosis. Three main approaches are used: (1) comparison of cells from patients with normal controls; (2) use of drugs to interfere with metabolism; and (3) characterization of various enzymes and enzyme systems implicated in phagocytosis. During the next 12 months, the patient studies will involve primarily cells with acute infection. Studies will include measurement of intracellular Na ion and K ion as a measure of membrane integrity as well as binding of serum components to the membrane by fluorescence microscopy. Drug studies will involve the effects of dialuric acid and phenazine methosulfate (two compounds which generate superoxide) on the metabolism and function of polymorphonuclear leukocytes. Other studies will center about defining the role of superoxide in the bactericidal process. An attempt will be made to directly demonstrate the generation of superoxide by phagocytizing neutrophils using the techniques of electron spin resonance (ESR).